Field of the Invention
The present invention relates to a method for preparing manganese-based nitride having nearly zero temperature coefficient of resistivity and more particularly, to the effective method for preparing manganese-based nitride expressed by the formula (1), wherein the manganese-based nitride, prepared by heating the stoichiometric mixture of Mn2N and Cu in an evacuated quartz tube, provides some advantages in that i) the use of the Mn2N compound as a reactant, the formation of impurities and nitrogen evaporation can be prevented, and ii) through nitrogen is tightly bonded between metals, the manganese-based nitride has extremely low (46 ppm/K) temperature coefficient of resistivity and a cubic antiperovskite structure.
CuNMn3xe2x80x83xe2x80x83(1) 
Temperature coefficient of resistivity (TCR) is an index of the changes of resistance with temperature and is determined by measuring the incremental change in resistance of a resistive material with temperature change, (1/R0)xc3x97(dR/dT), where R0 is the initial resistance. When the TCR value is close to that of zero TCR material is typically less than 25 ppm/K, the resistance change is less than 0.25% with 100xc2x0 C. of temperature difference.
Such materials having nearly zero TCR are widely used in the field of precision measurement and thin film resistor. Manganin, which is widely used as cryogenic resistor at very low temperature of 10 K, is an alloy comprised 84 wt. % of copper, 12 wt. % of Manganese-based and 4 wt. % of Nickel and used the most in precision measurement resistor. Manganin has about 20 ppm/K of resistance change with 10xc2x0 C. of temperature difference.
However, this alloy film possesses intrinsic problems of rapid increase in surface resistance due to oxidation on metal surface and poor adhesion due to large structural strain.
As a result of intensive studies to develop the compound having low temperature coefficient of resistivity, low structural strain and stable in air, the inventors have completed by providing stable CuNMn3 in air having a cubic antiperovskite structure.
An object of the invention is to provide a preparing method of manganese-based nitride having nearly zero temperature coefficient of resistivity which has more stability in air and higher adhesion then the metal alloy.